# Tcp Chat server

import socket
import select

# Function to broadcast chat messages to all connected clients


def broadcast_data(sock, message):
    # Do not send the message to master socket and the client who has send us
    # the message
    for socket in CONNECTION_LIST:
        if socket != server_socket and socket != sock:
            try:
                socket.send(message)
            except Exception:
                # broken socket connection may be, chat client pressed ctrl+c
                # for example
                socket.close()
                CONNECTION_LIST.remove(socket)


if __name__ == "__main__":

    # List to keep track of socket descriptors
    CONNECTION_LIST = []
    RECV_BUFFER = 4096  # Advisable to keep it as an exponent of 2
    PORT = 5000

    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    # this has no effect, why ?
    server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server_socket.bind(("0.0.0.0", PORT))
    server_socket.listen(10)

    # Add server socket to the list of readable connections
    CONNECTION_LIST.append(server_socket)

    print "Chat server started on port " + str(PORT)

    while 1:
        # Get the list sockets which are ready to be read through select
        read_sockets, write_sockets, error_sockets = select.select(
            CONNECTION_LIST, [], [])

        for sock in read_sockets:
            # New connection
            if sock == server_socket:
                # Handle the case in which there is a new connection recieved
                # through server_socket
                sockfd, addr = server_socket.accept()
                CONNECTION_LIST.append(sockfd)
                print "Client (%s, %s) connected" % addr

                broadcast_data(sockfd, "[%s:%s] entered room\n" % addr)

            # Some incoming message from a client
            else:
                # Data recieved from client, process it
                try:
                    # In Windows, sometimes when a TCP program closes abruptly,
                    # a "Connection reset by peer" exception will be thrown
                    data = sock.recv(RECV_BUFFER)
                    if data:
                        broadcast_data(sock, "\r" + '<' +
                                       str(sock.getpeername()) + '> ' + data)

                except Exception:
                    broadcast_data(sock, "Client (%s, %s) is offline" % addr)
                    print "Client (%s, %s) is offline" % addr
                    sock.close()
                    CONNECTION_LIST.remove(sock)
                    continue

    server_socket.close()
